Heating furnace



Patented Jan. 27, 1931 UNITED STATES PATENT OFFICE I HEATING FURNACEApplication-med January 8, 1929. Serial No. 331,015.

This invention relates to heating furnaces and method of firing saidfurnaces and, while not limited thereto, relates more particularly toheating furnaces particularly adapted for heating billets, sheet barsand the like, and to a novel method of firing said furnaces whereby thematerial being heated may be.

have substantially a uniform temperature at the exit or forward end ofthe combustion chamber. p

Another object is to provide a furnace of this class in which themaintenance cost Will be materially reduced since the flame is directedagainst the forward wall of the combustion chamber which is open andfree to complete circulation of air.

A further object is'to provide a furnace having materially increasedelliciency over furnaces of the prior art wherein the dame travel is ina single direction over the maw terial being heated.

In the drawings- Figure lis a longitudinal sectional view through afurnace constructed inV accordance with this invention andadapted tocarryy out this novel method.

Figure 2 is a transverse sectional elevation taken on the line II--IIofFigure 1.

Referring more particularlyto the drawings, the numeral 2 designates thefurnace' hearth which ris of the usual horizontal construction and isprovided with skid members 3 and 3*. The skid member-s3 are water cooledwhile the skid members 3 are solid uncooled members.

A low enclosing structure 4 is provided over the hearth 2. from the rearor entering end forwardly for a material distance and forms a lowchannel portion or heating chamber 5. The rear end of the enclosingstructure 4 is provided with an opening 6 through which the material tobe heated isl charged into the furnace.

Forward of the enclosingportion 4 an enclosing portion 7 is providedwhich is built up a material distance above the portion 4 and extendsforwardly to the forward or discharge end of the furnace and forms acombustion chamber 8. The ends vof the vchamber 8 are closed by rear andforward end Walls 9 and 10, respectively. The forward end wall 1() isprovided with an opening 12 through which the heated material; isdischarged.

A vertical flue 13 is provided at the rear end of the chamber 5 and ex.ends downward ly and connects with a horizontal flue 14 which extendsforwardly under the furnace and delivers the products of combustion andheated gases to an suitable recuperator or regenerator (not shown) whichis ada. ted

to supply preheated air to the burners o l thelivered thereto/from amain conduit 18 and `.branch conduits 19.

lt will be yunderstood that this invention vis not limitedto the 'use ofgaseous or liquid .fuel burners in the-chamber 8, since any fuel .forunderring vinthe ordinary manner so as to impinge'a flame against theunderside of the'material being heated.

The operation 'of he` above described furnace' when carryin out themethod of this invention is as fo ows:

Assuming that the furnace is charged and in operation, the flame fromthe burners 16 will be forced forwardl in a substantially horizontalplane throug the up er portion of the combustion chamber 8 until itstrikes the forward wall 10 of the chamber, which wall will force thedame-body to turn downwardly toward the furnace hearth 2 and the flamewill then be compelled to flow rearwardly in seeking an escape in adirection oppositely to that of the movement of the material beingheated. This rearward iow or travel of the flame will be aidedmaterially by the draft from the iues 13 and 14 and the fiame will thusbe drawn the entire length of the furnace hearth. By causing a reverseflow of the flame-body so that the upper and lower portions thereof are{iowing in opposite directions,a vertical horse-shoe sha ed travelingflow-body of flame is provide in the combustion chamber 8 above thematerial being heated. The upper or forwardly traveling portion of theiow body of ame is the hottest and the lower 'or rearwardly travelingportion is the coolest. Therefore the coolest flame is in contact withthe metal being heated while the hottest ame is separated by the coolerfiame from the metal and heats the metal by radiation only.

B-y providing this novel liow of the flame, the length of flow for agiven length of combustion chamber is increased, the hottest ame isprevented from impinging directly on the metal, a more uniformtemperature throughout the combustion chamber is had, and asoaking'condition is provided since the hottest a'me temperature is overthe cool metal as it enters the combustion chamber,

' and both the gases and steel are substantially at a uniformtemperature at the forward or dischar e end of the furnace.

Anot er feature resulting from the novel method of ring of thisinvention is that the wall l0 against which the flame im ,inges is freeto have a complete circulation o air over its outer surface. Thereforesaid wall will have a materially increased life andymaintenance costwill be materially reduced over that resulting when the ame is directedagainst the rear wall, as is ordinarily the practice.

A stillfurther advantage resulting from the novel method of firing ofthis application is that the infiltration of cold air through thedischarge port or opening 12 is substantially prevented due to the forceof the flame at this point.

Many other advantages resultl from my novel method and will be apparentto those skilled in the art.

While T have shown and described one specie embodiment of my inventionit will be understood that l do not wish to be limited thereto, sincevarious modifications may be made without departing from the scope of myinvention as defined in the appended claim.

I claim:

A continuous heating furnace for heating billets, sheet bars and thelike, comprising top, bottom, side and end walls, said top wall'. beingstepped upwardlyv from a point interi' mediate the ends of said furnaceto one end wall to form a high' combustion chamber of more thanone-third the total length of the. furnace, the end wall farthest fromsaid high combustion chamber being provided with an. inlet port throughwhich the material to be heated enters said furnace and the other endwall closing the forward end of said high combustion chamber beingprovided with an outlet port opening to the atmosphere through which theheated material is discharged, at least one fuel burner mounted lin theback wall of said high combustion chamber adjacent the top thereof anddirecting a flame against the forward end wall of said furnace, and afiue connection adjacent the rear or entering end of said furnace, saidfiue communicating with the interior of said furnace through the bottomwall thereof below the material being heated, said burner and said flueAbeing arranged to cause the flame after being projected toward theforward end wall of said furnace to reverse and flow back along saidfurnace under the flame body issuing from said burner and then continuerearwardly in contact with the material to be heated throughout thelength of said furnace.

In testimony whereof, I have hereunto set my hand.

ALBERT L. CULBERTSON.

